The role of insulin like growth factor (IGF)-1 and IGF-binding protein-3 in diagnosis of Growth Hormone Deficiency in short stature children

Abstract

Objective: The purpose of this study was to evaluate the role of IGF-1 and IGFBP-3 in diagnosis of short stature children and adolescents in whom Growth Hormone Deficiency (GHD) was found.

Methods: In this cross sectional study the referred short stature children and adolescents to Namazi Hospital in Shiraz- Iran, in 2003-2005 were studied. The inclusion criteria were proved short stature based on the physical examination, weight, height, standard deviation score (SDS) of height < -2, with considering stage of puberty and predicted height in children without any genetic or chronic disorders. The exclusion criteria were any positive physical or laboratory data suggesting hypothyroidism, rickets or liver disorders. For all patients a provocative growth hormone test was performed with propranolol and L-dopa and serum IGF-1 and IGFBP-3 were measured. GHD defined as peak(cutoff) serum GH level under 10 ìg/L and low IGF-1 and IGFBP-3 considered as cutoff serum level under -2 standard deviation.

Results: Eighty one short stature patients (39 boys and 42 girls) with mean age of 10.6 +/- 3.5 years completed the study. Seventeen patients with GHD were found and in 18 patients IGF-1 level were low. Only in 6 patients both GH and IGF-1 were low and 2 of them had low IGFBP-3. There were no correlations between the levels of GH,IGF-1 and IGFBP-3 in children with short stature due to GHD. The sensitivity and specifity of IGF-1 and IGFBP-3 in assessment of GHD were 35% and 81% for IGF-1 and 12% and 94% for IGFBP-3, respectively.

Conclusion: No correlations were found between GH level and serum levels of IGF-1 and IGFBP-3 in short patients and the sensitivity of those tests in assessment of GHD were poor.